1. Field of the Invention
The invention relates to a front light module and a display, especially to a super slim front light module and an electronic paper display.
2. Description of the Related Art
Front light modules for transflective or reflective displays are commonly of edge-lighting type or direct-lighting type, wherein the front light modules of edge-lighting type are becoming dominant due to the market's growing demand of small form factor on displays.
Please refer to FIG. 1, which illustrates a top view of a prior art front light module for providing a plane light to illuminate a reflective or transflective display. As illustrated in FIG. 1, the prior art front light module includes a line light assembly 100 and a light guide plate 110.
In the front light module, the line light assembly 100 includes a plurality of LEDs 101 packed tightly therein, to provide a line light.
The light guide plate 110 has a side surface neighboring the line light assembly 100 as a light entrance surface, and the bottom surface as a light exit surface, wherein the light entrance surface is used for receiving the line light, and the bottom surface is used for outputting a plane light.
However, it takes a lot of LEDs to make the line light assembly 100 output a uniform line light, and a lot of LEDs not only consume a lot of power, but also create a heat accumulation problem, which would require additional heat dissipating means.
To reduce the number of LEDs, some prior art front light modules add diffusion points in a strip region behind the light entrance surface of the light guide plate. Please refer to FIG. 2, which illustrates a top view of another prior art front light module for providing a plane light to illuminate a reflective or transflective display. As illustrated in FIG. 2, the prior art front light module includes a line light assembly 200 and a light guide plate 210.
In the front light module, the line light assembly 200 includes a plurality of LEDs 201, which are loosely packed therein, to provide a line light.
The light guide plate 210 has a side surface neighboring the line light assembly 200 as a light entrance surface, and the bottom surface as a light exit surface, wherein the light entrance surface is used for receiving the line light, and the bottom surface is used for outputting a plane light. The light guide plate 210 has a diffusion region 211 behind the light entrance surface of the light guide plate 210, wherein the diffusion region 211 has a plurality of diffusion points 2111 for scattering the incident light beams of the line light to improve the uniformity of the plane light.
Compared with the front light module of FIG. 1, the front light module of FIG. 2 uses less LEDs, but it adds in the diffusion region 211. As the diffusion points 2111 in the diffusion region 211 can interfere with a user's viewing a display, the area of the light guide plate 210 has to be larger than the visible area of the display to avoid impacting the display quality. As a result, the design of FIG. 2 is not good for the form factor of the display.
In view of the foregoing problems, the invention proposes a super slim front light module having a structure for guiding light downward.